develops between 6 weeks to 6 months postpartum with an incidence of about 5% to 10% of all women [12]. This is followed by a hypothyroid state with a return to baseline after about 1 year, although some women may develop permanent hypothyroidism. There is usually a small, nontender goiter, and symptoms are usually mild, the result of either the hyperthyroid or hypothyroid state. There is approximately a 70% chance of recurrence in subsequent pregnancies in those who had postpartum thyroiditis with their first pregnancy [12]. Sporadic thyroiditis is a condition similar in clinical course to postpartum thyroiditis, but it is not associated with pregnancy [11]. Up to 20% of these patients eventually develop lasting hypothyroidism. Suppurative thyroiditis is an infection of the thyroid gland typically caused by a bacterial infection, and less commonly by fungal, mycobacte- rial, or parasitic infections [11]. Although rare, it is more common in those with pre-existing thyroid disease and in immunocompromised patients. Clinical features include a painful thyroid gland (anterior neck pain with erythema), fever, dysphagia, and dysphonia. Amiodarone-induced thyroiditis is associated with either symptomatic or asymptomatic hyperthyroidism. It occurs in about 10% of patients in iodine-deficient areas, and less commonly in iodine-replete areas [7]. The mechanism of thyroid dysfunction from the use of amiodarone is caused either by the release of the iodine from the drug itself or by the development of destructive thyroiditis. Individuals with underlying autoimmunity are at increased risk for developing hyperthyroidism if they are taking amiodar- one. Nodular and multinodular goiters, which are more common in the elderly, are a predisposing factor for amiodarone-induced thyroiditis [7]. Clinical features Thyroid hormone affects nearly every organ system in the body. Patients with elevated thyroid hormone present in a hypermetabolic state with signs of increased b-adrenergic activity. Severity of the symptoms and signs of thyrotoxicosis are related to the duration of the disease, the magnitude of thyroid hormone excess, and age [13]. Although the diagnosis is frequently straightforward in patients with overt features of hyperthyroidism, a high degree of clinical suspicion has to be exercised in those with subtle clinical features of hyperthyroidism. History Constitutional Many nonspecific complaints are common, particularly when hyperthy- roidism is not yet advanced or when it occurs in the elderly. Complaints such as fatigue, nervousness, or anxiety can lead one to consider a 672 MCKEOWN et al Recognition and Management of Adrenal Emergencies Susan P. Torrey, MD a,b a Tufts University School of Medicine, 136 Harrison Avenue Boston, MA 02111, USA b Department of Emergency Medicine, Baystate Medical Center, 759 Chestnut Street, Springfield, MA 01199, USA Case 1. A 52-year-old woman presents to the emergency department (ED) with the chief complaint of palpitations, sweating, and chest tightness. This has been a recurrent problem for the patient over the prior 6 months. She has been treated with benzodiazepines by her primary care provider. Although the sympto ms are improving on presentation to the ED, she says she felt like she was going to die. PMH is otherwise negative. She does not smoke and denies drug or regular alcohol use. Exam in the ED includes: vital signs: 188/104, 108, 20, 98.8  F, oxygen saturation 98%; lungs: clear without wheeze or rales; cardiac: regular without murmur; abdomen: soft, nontender; neurologic: nonfocal exam. Is this simply another presentation of an anxiety attack in the ED? Pheochromocytomas Pheochromocytomas are notorious but rare catecholamine-secreting tumors of neuroectodermal origin. There are several clinical issues of importance to emergency physicians, ranging from the potential for presentation as a hypertensive emergen cy to the recognition of more subtle symptoms masquerading as yet another anxiety attack. Although pheo- chromocytoma will be diagnosed or treated infrequently in the emergency ED, it is an important entity to consider in the differential diagnosis of several presentations . Pheochromocytomas can occur anywhere along the sympathetic chain, although 85% to 90% are discovered within the adrenal gland. In adults, at least 10% are extra-adrenal; 10% are bilateral, and 10% are malignant, with E-mail address: susan.torrey@bhs.org 0733-8627/05/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.emc.2005.03.003 emed.theclinics.com Emerg Med Clin N Am 23 (2005) 687–702 Bone and Mineral Metabolism John Sarko, MD Department of Emergency Medicine, Maricopa Medical Center, 2601 E. Roosevelt Street, Phoenix, AZ 85008, USA In addition to providing strength, support for the body, and serving as the attachment for muscles to allow movement to occur, bone is extremely active on a metabolic level and is important in the regulation of several endocrine functions. It is the major source of calcium; it buffers against acidosis, and can adsorb toxins and heavy metals. Calcium, phosphate, and magnesium are minerals vital to the function of all cells. They are tightly regulated by several hormones, and disorders in their metabolism are common. In this article, bone structure and function, and mineral metabolism are reviewed. Conditions leading to bone loss are discussed, as diseases increasing bone density are rare and less likely to be encountered by emergency physicians. Bone and bone metabolism Anatomy of bone Bone comprises approximately 14% of the adult weight. Two types of bone exist: cortical (compact) and cancellous (spongy) [1]. Compact bone comprises 85% of the skeleton, is strong, solid, and very organized. Its basic structural unit is the Haversian system (osteon), a cylindrical entity that runs along the long axis of the bone (see Fig. 1). It is comprised of concentric rings of matrix called lamellae, which contain small holes called lacunae with an osteocyte in each. The center of the Haversian system is an opening called the Haversian canal, which contains blood vessels and nerves. Haversian canals and lacunae are connected to each other by canaliculi that are oriented parallel to the horizontal axis of the bone. Cancellous (spongy) bone makes up 15% of the skeleton, and most bones contain at least some of each type. The vertebrae are predominately E-mail address: sarkoj@yahoo.com 0733-8627/05/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.emc.2005.03.017 emed.theclinics.com Emerg Med Clin N Am 23 (2005) 703–721 . discovered within the adrenal gland. In adults, at least 10% are extra-adrenal; 10% are bilateral, and 10% are malignant, with E-mail address: susan.torrey@bhs.org 0 73 3-8 627/05/$ - see front matter Ó 2005. makes up 15% of the skeleton, and most bones contain at least some of each type. The vertebrae are predominately E-mail address: sarkoj@yahoo.com 0 73 3-8 627/05/$ - see front matter Ó 2005 Elsevier. rights reserved. doi:10.1016/j.emc.2005. 03. 0 03 emed.theclinics.com Emerg Med Clin N Am 23 (2005) 687–702 Bone and Mineral Metabolism John Sarko, MD Department of Emergency Medicine, Maricopa